Sound recording system



March 19, 1935.

W. M. PATTERSON SOUND RECORDING SYSTEM Filed June 11, 931

2 Sheets-Sheet l jive/away WITN ESSES I INVENTOR William MPaffersa/r.

ATTO NEY March 19, 1935. w, M. PATTERSON 1,994,920.

SOUND RECORDING SYSTEM 2 Sheets-Sheet 2 Filed June 11, 1931 WITNESSES:INVENTOR William Pai'frsofl. 9g "14 ATTORNEY Patented Mar. 19, 1935emanates PATENT orr ce SOUND RECORDING SYSTEM Application June 11, 1931,Serial No. 543,507

12' Claims.

graphic apparatus and has particular relation to apparatus of a typewherein a directional effect is introduced into the sound reproducedwith a motion picture that corresponds to the elements of the picturethat are shown sound.

In acousto-cinematographic apparatus conto produce the structed andoperated according to the teachings of the prior art, of which I amaware, the sound is reproduced from a plurality of loudspeakers disposedadjacent to the screen in with some prearranged scheme. The

accordance loudspeakers are, at any instant, all energized to the sameextent and. in consequence thereof, emanating from the region of the scrproperty of homogeneity in direction.

the sound can has the The points on the screen from which the soundshould emanate vary as persons depicted appear tomove across the screen.an arrangement is rather strange an even ludicrous. Moreover, when a Theeffect produced bysuoh d, at times, number of persons are portrayed asspeaking simultaneously, the result is rather confusing to the audience,since the sounds that are shown as coming from the characters cannot bedistinguished.

It is, accordingly, an object of my invention to provideacousto-cinematograp'hic apparatus wherein the sound reproduced shallrectional characteristic.

have a di- Another object of my invention is to provideacousto-cinematographic apparatus wherein the sound produced shallemanate from a screen corresponding to the position ture element bywhich the sound is produced.

A further object of my invention is acousto-einematographic apparatuswherein the elements of a picture from which a plurality of sounds areapparently region of a of the picapparently of a type emanating shall bedistinguishable by reason of the direction in which the sound isactually being projected.

A specific object of my invention is to provide a recording device of atype wherein a record shall be impressed on a permanent.

medium in such manner that the relative disposition of the elements fromwhich the original soun shall be distinguishable.

d emanated recorded was projected.

A still further specific object of m y invention to provide My inventionrelates to acousto cinematois to provide cine-acoustic recordingapparatus of a type wherein the recording elements shall respond to therelative disposition of the objects fromwhich the sound to be recordedis emanating.

Still a further specific object of my invention is to providereproducing apparatusof a type wherein the sound emanating from a givenregion shall have a predetermined heterogeneity in direction.

Another specific object of my invention is to ,0 I

provide reproducing apparatus of a type wherein the sound emanatingfroma given region shall have a heterogeneity in direction that shall beso variable with respect to time as to correspond to the pictureprojected. Y

.Still another specific object of my invention is to provide reproducingapparatus to be utilized in an acousto-cinematographicj system of a typewherein the sound reproduced shall emanate from regions predetermined bythe disposition of the elements in the recording setting.

An incidental object of my'invention is to provide a sound recordparticularly adapted to be utilized in directionalacousto-cinematographic apparatus. V

A further incidental object of my invention is to provide a sound recordof a type having a property whereby the directional efiects of soundshall be capable of being recorded.

1 Another incidental object of my invention is to provide aphoto-sensitive device particularly adapted to be utilized indirectional cinemaacoustic reproductions Still another incidental objectof my invention is to provide a photo-sensitive device to respond tolocalized excitation in a predetermined manner.

A still further object of my invention is to provide a photo-sensitivedevice that shall be capable of responding to localized excitation in amanner that shalllend itself to the spacial prearrangement of elementsenergized by the device. 7 f

More concisely stated, an object of my invention is to providereproducing and recording apparatus of atype that shall cooperate inproduc-. ing acousto-cinematographic entertainment wherein the elementsof a picture from which a sound appears to emanate shall correspond, ina natural and expected manner, to the original source of-such sound.

According to my invention, a plurality of de- Vices for translatingacoustic disturbances in the air into electrical energy,; such asmicrophones, are disposed in a predetermined manner in the vicinity of asetting to be photographed and 55 recorded. The sound impressed on themicrophones is amplified and the outputs of the amplifiers feed into theexciting element of a light valve of a type, well knownin the art, suchas a recording galvanometer or a Kerr cell.

At a predetermined point in each recording amplifier, certain of thetranslated electrical energy-is tapped oif and is fed into an averagingdevice.

The averaging device has a balanced structure and is responsive to thedifference in the mag-nitude of the energy fed to itfrom the individualamplifiers. The output of the balanced averaging device feeds into anexciting coil that regulates the position of a galvanometer mirror, andthe mirror is thereby deflected in a direction corresponding to thepredominating amplifier. The magnitude of the deflection corresponds tothe average energy impinging on the sensitive element of the microphonecorresponding to the predominating amplifier.

The recording light beam is modified by the light valve and is deflected.by the mirror in a manner predetermined by the condition of thesound-translating devices and their corresponding amplifiers. Arectangle is thus imagedlon a film strip that has a width large incomparison with the long dimension of the rectangle, and the lateralposition on the film at which the rectangle is imaged corresponds to theposition of "the most highly excited microphone- That is to say, theposition of the sound track' on the film corresponds to the position ofthe object from which the sound of maximum intensity is being emitted.

When the film thus energized is printed and developed, a record isproduced wherein the sound track has a lateral variation in positionwhich corresponds to the variation in position of the bodies in therecording setting that originally emitted the sound.

The record is reproduced in a manner well known in theart. That is tosay, an attenuated light beam is projected on the film and is modifie'din 'accordancewith the character and-disposition of the sound track.After being modified, the light impinges on the photo-sensitive elementsof an elongated photo-sensitive device particularly adapted for thepresent purpose.

The photo-sensitive device prefer-ably comprises a plurality ofphoto-sensitive electrodes and a plurality of collecting electrodesassociatedtherewith. The collecting elements are dis* posed adjacent tothe photo-sensitive elements and the electrodes are connected inindependent circuits in such manner that energy is transmitted to thecircuits inaccordance with' the locali- Zation of the light beamexcitingthe element.

The circuits into which the photo-sensitive electrodes feedare connectedto independent amplifiers which, in turn, feed into "independent loudspeakers disposed adjacent to picture-reproducing screen in a mannercorresponding to the original disposition of the microphones adjacent tothe photographing stage. The amplitude of the sound produced in the loudspeakers corresponds to the lateral disposition of the sound track onthe film and, therefore, corresponds to the original disposition of theobjects emitting the sound. a

The novel features that I consider characteristic of my invention areset forth with particularity in the appended claims. The inventionitself, however, both as to its organization and .its method ofoperation, together with additional objects and advantages thereof willbest be un- 5 disposed adjacent thereto. and '5 feed intoa plurality ofindependent ampliderstood from the following description of a specificembodiment, when read in connection with the accompanying drawings, inwhich:

Figure 1 is a schematic drawing showing a recording system constructedaccording to my invention;

Fig. 2 is a diagrammatic view showing the essential elements of theaveraging device in its relation to a record amplifier and the recordinggalvanometer;

Fig. 3 is a schematic view showing areproducing system providedaccording to my invention;

Fig. 4 is a schematicview showing a photosensitive device particularlyadapted to be utilized with apparatus constructed in accordance with myinvention and the input elements for the amplifiers cooperatingtherewith; and

Figs. 5, 6, 7-and 8 are modifications of photosensitive devices that maybe utilized in the practice of my invention.

The apparatus shown in Figs. 1 and 2 comprises a stage 1 having aplurality of microphones 3 and The microphones 3 fiers 7 and 9, and theoutput terminals 11 and 13 of the amplifiers are connected in parallelto .a coil 15 whereby the position of the movable element 1? of agalvanometer 19 is predetermined.

The position of the movable element 17 of the galvanometer I9 ismicroscopically responsive to the energy transmitted to the excitingcoil 15 from the amplifiers [and 9. By reason of its instantaneousvariations in position, a light beam from a suitable source 21, which issuitably modified by an optical system '23,.is deflected to produce animpression of variable width on a film strip 25 on which it impinges.

The above describedrecording process is well known in the art. However,according to my invention, the line of zero current-modulation of.thesound track 2'? on the film 25 is shifted in accordance with theposition of the object fron which the sound to be recorded is emanating.

The energy delivered by a predetermined element of the amplifiers 7 and9 is fed into an averaging device 29. The averaging device has an outputresponsive to the influence of one of the amplifiers 7 and "9 in whichthe translated electrical energy predominates and feeds into theexciting coil 31 of a second galvan'ometer 33. The

a function of the disposition of the elements 210- Y wally-emitting thesound.

Although the system of recording illustrated herein is of thevariable-area type, a record of the variable-density type may beproduced in accordance with my invention in a manner which is apparent.In such a case, an optical valve,

such as a Kerr cell, for example, is d sposed be-- light valve of theglow-lamp type may be utilized, in which case, the source is sodisposed'relative' to the microscopically-responsive mirror 35 that thelight therefrom is suitably deflected before it impinges on the film.

1 Finally, it should be noted that, whi1e,'in' the illustratedembodiment of my invention, two galvanometers are utilized, my inventionmay equally as well be practised with a single galvanometer that isbiased in response to the directional effect of the sound and thatresponds to the instantaneous variations introduced by reason of thecharacter of the sound in its biased positions.

In Fig. 2, a portionof one of the amplifiers 7- and 9, together with theaveraging device 29, is shown in detail.

Each of the microphones 3 and 5 is connected in the grid circuit of anamplifier tube 37,in the plate circuitof which the primary windings 39and 41 of a plurality of transformers 43 and 45 are connected. Thesecondary winding 47 of one transformer 43 is connected to the input'ofthe next stage of amplification of the system, while the secondary 49 ofthe other transformer 45 is connected to the terminals of a ballast lamp51 that comprises one arm of abalanced circuit, such as a Wheatstonebridge. A balanced lamp 53, fed, ina similar manner, from the firststage of amplification of the other amplifier 9, is connected in aconjugate armof the bridge and. the coil 31, whereby the mirror 35,responsive to the microscopic condition of the sound, is actuated, beingconnected between two conjugate terminals 55 and 57 of the bridge.

The bridge is adjusted by a plurality of variable resistors 59 and 61 insuch manner that zero current is transmitted throughthe exciting coil 31of the microscopic galvanometer 33 when the sound energy impinging onone of the microphones 3 and 5 is substantially equal to that on theother. As the sound impinging on the microphones varies, the resistanceof the ballast lamps 51 and 53. corresponding to the microphones,varies, and, if the system becomes unbalanced,'current is transmitted tothe coil 31 of'thegalvanometer 33. The reflector 35 associated therewithis then deflected in such manner that the recordinglight beam impingeson the film 25 in a region'corresponding to the relative magnitude ofthe predominating sound emitted and to the disposition of the soundemitters' c It will be apparent to those skilled in the-art that theballast lamps .51 and53 may be replaced by resistors of other types thatrespond with facility 'to' variations in current transmitted throughthem. Forexample, grid-controlled ther mionic tubes may be utilized inlieu of the lamps 51' and 53. In such case, the plate circuits of thetubes constitute the arms of the bridge, while the grid currents of thetubes are fed, from the amplifiers 7 and 9.

In Fig. 3, a reproducing system is shown schematically. The systemcomprises a light source 63, a condensing lens 67, wherebythe radiationsfrom the source 63 are gathered and focused on a slot 69, and a lenssystem 71 whereby the slot 69 is imaged on the film 25 in the form of anattenuated rectangle, .73 extending across the film 25. i

A photo-sensitive device 75, comprising an elongated container 77 havingdisposed therein, a plurality of independent cathodes 79 and anodes 81,is located behind the film 25. The light transmitted through the film 25and modified by the "the same character.

their disposition in the photo-sensitivedevice, and

their state of'excitation is dependent on the lateral orientation of thesound track on the film.

The current produced between each cathode 79 and its corresponding anode81 is fed into a plurality of independent amplifiers 83, 85 and 87,which, in turn, feed into a plurality of loud speakers 89, 91 and 93,The loud speakers 89, 91 and 93 are arranged in the vicinity ofthepicture screen (not shown) in a manner corresponding to themicrophones 3 and ,5 in the recording setting, and it is seen thatlthemagnitude of the sound reproduced by the loud speakers willbedependenton the state of excitation of the individual cathodes 79 and,therefore, on the original disposition of the sound-emitting bodies inthe recording setting.

.It is well to keepin mind that theloud speakers may be disposed behindthescreen or adjacent to the screen, in a manner dictated byexpe'riencein installation. Moreover, the amplifiers 83,85 and 87 and the speakers89, 91 and 93-need not be of V In certain reproducing equipment, I havefound that the central ampli fier 85 and its corresponding speaker 91should preferably be capable of delivering more volume per unit'inputthan the other'repi oducing merribers. By reason ofsuch anarrangementythe amplification applied to the amplifiers transmitted tothe terminal speakers: 39 and 93may be so limited that they do notbecome overloaded even if the original sound on one side of the stage"lis comparatively loud.

In Fig. 4, a photo-sensitive device 95 of a type having a common cathode97, a plurality of principal anodes 99 and a plurality of auxiliaryanodes 101 is shown. The cathode 97 and the principal anodes 99 arerespectively connected to the terminals'of a plurality of inductors 103which are" the input elements to a plurality of amplifiers.

It is apparent that the anode associated with the region of the cathodewherein the radiant energy'is localized will receive a greater chargethan the anodesassociated with the other regions of the cathode.Moreover, it is a Well known fact that photo-electrons are emitted fromthe surface, in general, in a direction perpendicular to-the surface.Consequently, if the cathode surface comprises a plurality ofcylindrical arcs 105 and the anodes 99 are disposed at the centers ofcurvature of the arcs, the result produced by radiant energy of alocalized character will correspond with comparative accuracy to thelocalization of type illustrated in Fig. 4 is particularly adapted to beutilized in apparatus of a type wherein the loud speakers in the centralregion of the repro ducting stage are, capable of delivering more poweroutput than the speakers in the terminal regions of thestage. a i

In Fig. 5, a photo-sensitive device '107 having a plurality ofindividual cathodes 109 and a plu- :rality of principal and auxiliaryanodes 111 and ,1l3associated with each cathode is shown. The purposeofrthe auxiliary anodes-113 in the photosensitive device 107 of the typeillustrated in Fig. .5 is thesame as the purpose of the correspondinganodes 101.,in the-device 95 of the type illustrated in Fig. 4.-

-, In-Fig. 6, a photor-sensitive device 115, comprising a single cathode117 having plural-arc configuration and a single anode 119 associatedwith-each arc, is shown.

In =Fig.'7, a photo-sensitived-evice 121, of a type having ;a planecathode 123 and a plurality of associated anodes 125, is illustrated.

In Fig. 8,,a photoesensitive device 12'7, incorporating a*cathode v121of the type having the configuration oi an are made up of a plurality ofreentrant smaller arcs 131 is shown. A plurality -of' anodes-133 areassociated with the smaller arcs 131.

Withthe exception of the photo-sensitive de- .vices that may be-utilizedwith my improved reproducing system, a single embodiment of my inventionhas been illustrated herein. The system has 'been shown, in general,schematically, and the improvements that are ordinarily incorporat-=ed=in photo-acoustic and recording, reproducing systems are not shown.It is understood, howeven thatapparatus incorporating these improvementsare equivalents which lie within the scope of my invention. Inparticular, it is set forth that a record constructed according to myinvention may incorporate; the ground-ncise-reducing features which arebeginningto be utilized inthe motion-picture art. .Again, it should benoted that, while modifications, of photo-cells having independentanodes and a common cath- :odeare illustrated and described hereinabove,my invention maybe equally as well practiced with photo-cells having acommon anode and aplurality of independent cathodes.

- Finally, it should also be added that a sound record utilized in thepractice of my invention should preferably be of the negative type. Thatis to say, the record should be of the type wherein; the sound trackregion is transparent while the remaining region is opaque. By utilizingsuch a record, difliculties from ground noise are eliminated. Forpurposes of clarity, a positive record is shown in Fig. 3.

Although I have shown and described certain specific embodiments of myinvention, I am fully aware that many modifications thereoi arepossible. My invention, therefore, is not to be restricted exceptinsofar as is necessitated by the prior art and by the spirit of theappended claims.

I claim as my invention:

'1. Directional photographic acoustic-recording apparatus comprising aplurality of devices for translating acoustic energy intoelectricalenergy, said devices to be distributed in the region where the sound isto be produced, means for averaging the electrical energy produced ineach translating device todisplace the beam in accordancewith :thesource of sound, a medium for receiving impressions of said translatedelectrical energyand aneans for localizing said impressions on said medium in accordance with the magnitude of the average energy producedfrom each of said trans-' lating devices.

2. Directional acoustic-recording apparatus "comprising a pluralityofdevices for translating acoustic energy into electrical energy, saiddevices to be distributed in the region where the sound is to bereproduced in such-manner that the magnitude of the electrical energydelivered byeach of said translating devices for a given sound isdependent ,on the .relative position of .the emitter of said sound,amedium for receiving disposition of the source of said acoustic energy,

and means for producing a permanent physical impression of saidelectrical'energy, the last said means varying the location -of saidphysical impression responsive to the directional-effect produced insaid translating means. a

4. In apparatus for recording sound, means for producing an attenuatedbeam of radiant energy,

condition of the sound to be recorded, and means for laterallydisplacing said beam in accordance with the relative position of;.thesource of said sound, the magnitude of said lateral displacement beingdependent on the distance of said source from a predetermined point.

5. In a system for recording sound in combination a balancednetwornhaving in each -of a plurality of arms thereof a idevicecapable ofresponding to the average value of the electrical energysuppliedthereto, the output of'said network being responsive. to therelative conditions ofsaid energy-responsive devices in each of the armsthereof, means for independently supplying electrical energyto each ofsaidenergy-responsive devices, means for projecting a light beamandmeans, to be actuated by the-output of said network, for deflectingsaid light .beam in accordance with the relative condition of each ofsaid energy-responsive devices. v

6. In combinationa plurality of devices for converting acoustic energyinto electrical energy, a balanced network having, in each of aplurality of arms thereof, a device capable of responding to the averagemagnitude of the electrical energy supplied thereto, the output of saidnetwork being responsive to the relative conditions of saidenergy-responsive devicesin each of the arms thereof, means for couplingone of said energyconverting devices to each of said energy-responsivedevices, means for projecting a beam of radiant energy and means, to beactuatedby the output of said network, for deflecting said beam ofradiant energy in accordance with the relative conditions of. saidenergy-responsive devices.

said translating devices relative to that of the' others varies inaccordance with the variation of the lateral position of said record onsaid film strip.

8. In combination a film strip carrying a sound record,.said recordbeinglaterally displaced .on

said beam being responsive to the instantaneous acoustic energy of anyof said translating devices relative to that of the others varies inaccordance with the variation of the lateral position of said record onsaid film strip.

9. Apparatus for reproducing sound comprising a plurality of devices fortranslating electrical energy into acoustic energy, a medium havingpermanently impressed thereon a single record carrying'the combinedimpression of the sound to be reproduced and of a predetermined spacedistribution of said sound in the region of reproduction'and means, tobe energized in accordance with the impressions of said record on saidmedium, for supplying electrical energy to said translating deviceswhereby a sound is produced having a-quality and a distributioncorresponding to said record.

10. In combination a film strip carrying a sound record, said recordbeing laterally displaced on said film strip and the magnitude of saidlateral displacement being varied in a predetermined manner, means forconverting said record on said film strip into electrical energyvariations, said means including a photo-sensitivedevice having a singlecathode and a plurality of anodes to cooperate with said cathode andoptical means for so projecting the impression on said film strip onsaid photo-sensitive device that the current in said device flowsbetween said cathode and one of said anodes selected in accordance withthe lateral position of said impression on said film strip, a pluralityof devices for translating electrical energy into acoustic energy andmeans for supplying said electrical energy variations to saidenergy-translating devices in such manner that the response of saidtranslating devices varies in accordance with the variation of thelateral position of saidimpression on said film strip.

11. In combination a film strip carrying a con- 7 tinuous sound record,said record being laterally displaced on said film strip and themagnitude of said lateral displacement being varied in a predeterminedmanner, means for converting the record on said film strip intoelectrical energy variations, said means including a photo-sensitivedevice incorporating a plurality of pairs of elements, each elementcomprising a cathode and anode, in a single container, and optical meansfor so projecting the record'on said film strip on said photo-sensitivedevice that the current in said device at any time flows between one ofsaid pairs of elements selected in accordance with the lateral positionof said impression on said film strip, a plurality of devicesfiortranslating electrical energy into acoustic energy and means forsupplying said electrical energy variations to said energy translatingdevices in such manner that the output acoustic energy of any of saidtranslating devices varies relative to that of the others in accordancewith the variation of the lateral position of said record on said filmstrip.

12. Apparatus for reproducing sound comprising a plurality of devicesfor translating electrical energy into acoustic energy, aphoto-sensitive .device that is capable of selectively responding inaccordance with the localized efiect of radiant energy impingingthereon, a medium having impressed thereon a single record of sound,said record being localized in said medium in a man ner corresponding toa predetermined distribution of said sound in the reproducing medium,means for energizing said photo-sensitive device in accordance with saidrecord and means for energizing said translating devices in accordancewith the output of said photo-sensitive device.

WM. MAURICE PATTERSON.

